arch/x86/kernel/eisa.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * EISA specific code
   4  */
   5 #include <linux/cc_platform.h>
   6 #include <linux/ioport.h>
   7 #include <linux/eisa.h>
   8 #include <linux/io.h>
   9
  10 #include <xen/xen.h>
  11
  12 static __init int eisa_bus_probe(void)
  13 {
  14         u32 *p;
  15
  16         if ((xen_pv_domain() && !xen_initial_domain()) || cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
  17                 return 0;
  18
  19         p = memremap(0x0FFFD9, 4, MEMREMAP_WB);
  20         if (p && *p == 'E' + ('I' << 8) + ('S' << 16) + ('A' << 24))
  21                 EISA_bus = 1;
  22         memunmap(p);
  23         return 0;
  24 }
  25 subsys_initcall(eisa_bus_probe);